Synthesis and characterization of new 10- and 12-vertex CO-ligated metallathiaboranes

Abstract The reaction between [ arachno -6-SB 9 H 12 ] − and [IrCl(CO)(PMe 3 ) 2 ] affords the previously reported 11-vertex cluster, [8,8,8-(CO)(PMe 3 ) 2 - arachno -8,7-IrSB 9 H 10 ] ( 4 ), and small amounts of the new 10-vertex iridathiaborane [9,9,9,9-(CO)(H)(PMe 3 ) 2 - arachno -9,6-IrSB 8 H 10 ] ( 5 ). Alternatively, a rational synthesis of iridathiadecaboranes is effected from the reaction of the 9-vertex anion [ arachno -4-SB 8 H 11 ] − with [ M Cl(CO)(PPh 3 ) 2 ], to afford new CO-ligated 10-vertex metallathiaboranes of formulation, [9,9,9,9-(CO)(H)(PPh 3 ) 2 - arachno -9,6- M SB 8 H 10 ], where M  = Rh ( 6 ) and Ir ( 7 ), in useful yields of 61% and 60% respectively. Treatment of the 11-vertex rhodathiaborane, [8,8-(PPh 3 ) 2 -8,7- nido -RhSB 9 H 10 ] ( 1 ) with n BuLi, followed by addition of [IrCl(CO)(PMe 3 ) 2 ] affords the 12-vertex iridarhodathiaborane, [1,2-( μ -CO)-1,1,2-(PMe 3 ) 3 -2-(PPh 3 )- closo -1,2-IrRhSB 9 H 9 ] ( 8 ) in low yield (0.7%). The 10-vertex metallathiaboranes, 5 , 6 and 7 , and the bimetallic 12-vertex cluster, 8 , have been characterized by multinuclear NMR spectroscopy. In addition, the molecular structures of compounds 5 , 6 , and 8 have been studied by X-ray diffraction.